Tips for DAG Exchange Backup and Replication in vSphere

• Place the Exchange Virtual Machines disks on the fastest disks (Datastores) that are available.
• Disable all background scanning and/or maintenance tasks occurring in Exchange, or any other tools that are being leveraged against the system at the time of backup.
• Perform the Exchange Backup singularly as opposed to concurrently with other jobs.
• Review cluster failover sensitivity using this command line tool and switch.
  See note below if running Server 2012 or newwer.
  

  cluster /prop
  

  Adjust Microsoft settings for failover sensitivity (in bold, run from command line)
  

  cluster /prop SameSubnetDelay=2000:DWORD ::(Default: 1000 in Server 2008 R2)
  cluster /prop CrossSubnetDelay=4000:DWORD ::(Default: 1000  in Server 2008 R2)
  cluster /prop CrossSubnetThreshold=10:DWORD ::(Default: 5  in Server 2008 R2)
  cluster /prop SameSubnetThreshold=10:DWORD ::(Default: 5  in Server 2008 R2)
  

• Add the line snapshot.maxConsolidateTime = "1" to the .vmx (configuration) file for the primary node.
  Please note that this is an undocumented vmx alteration, and should be validated by VMware support prior to using.
• Reduce total amount of disks (.vmdk's) for primary node if possible, reducing impact of snapshot operations.
• If the VM resides on a datastore backed by NFS storage, consider migrating the VM to VMFS storage.
• Test snapshot operations directly to ESX(i) host instead of vCenter. (In some cases, gaps in communication between vCenter and ESX(i) host can impact snapshot operations, including VSS operation timing.)

Note: With Server 2012 or newer cluster.exe may not be available, as such you will need to install and use the PowerShell cmdlets. The cmdlets may need to be enabled using the following command:

Install-WindowsFeature -name RSAT-Clustering-CmdInterface

View cluster settings:

Get-cluster | fl *subnet* - provides current settings for timeout

Adjusting cluster settings:

(get-cluster).SameSubnetThreshold = 20   #(Default 10 in Windows 2012R2+)
(get-cluster).SameSubnetDelay = 2000     #(Default 1000 in Windows 2012R2+)
(get-cluster).CrossSubnetThreshold = 40  #(Default 20 in Windows 2012R2+)
(get-cluster).CrossSubnetDelay = 4000    #(Default 1000 in Windows 2012R2+)